Oleoresinous varnishes and methods



Patented May 1, 1251 John J .Bradleygl Jn, Winchester, ...Massassigner.v to Boston Varnish Company, vEverett,.Massr., a. corporationof Massachusetts No Drawing. .Application July 20; :1948; Serial No.39802 'I'his invention relates to oleoresinous' varnishes and moreparticularly to an oleoresinous varnish of improved characteristicsandmethods of making the same from glyceride oils, or mixtures thereof, inwhich appreciable proportions of the double bonds are in conjugatedpositions.

The conjugated unsaturated glyceride oils, such as China-wood oil,oiticica oil, isomerized linseed oil or dehydrated castor oil, are adesirable 'type of glyceride oil for the manufacture of oleoresinousvarnishes, either alone or as a part of a batch containing other dryingoils in which conjugationy is slight or absent, suchv as. linseedoil,but the processing o"f batches in.which.an.appreciable proportion of thedouble bonds of the glyceride oil is conjugated on a commercial scale 4claims. (o1. 10G-222' y conventional heat. bodying processes, and vprov.

lili

by thel traditional varnish-makersprocedure, has

presentedveryserious difficulties;

Oils of the conjugated-:maturationtypegk e. g., China-wood oil, havecriticalpolymerizationtem-` peratures (500g-550 -F.), above which'thereaci-A f tion is exothermic and diflicult: to control, and: theyrapidly advance toa high viscosity'orusenV less gel state. If lower andsafer temperatures are employed, the resulting varnish'generallyhasinferior film forming `properties, poor` drying characteristics and poorresistance'toJ Water 'and to chemicals. Thus, only aV fewresins-wil1igas` proof China-wood oil `below '500o` F. andi none belowabout 450 F,- In addition, as pwith other glyceride oils, theseconjugated unsaturated oils;. andA the resin which is'presentA with'themi'nya varnish composition, 4darken rapidly inthe. varnish kettle at therequired high temperatures', above 400 F., due to oxidation. Whenlighter colored products are required, the'heatingv must be carried outin an atmosphere. of an inert gas, such as carbon dioxide `or nitrogen,to prevent' oxidation. The use of such gasesis inconvenienty andexpensive. Also, the heretofore unavoidable high temperaturesemployedresult in substantial losses of material due to decomposition.`and volatilization and due to formation of insoluble skins or gelswhich must be discarded.

An object of the invention is to provide an' oleo-resinous varnish ofsuperior drying` and' nlm-forming characteristics.

Another object of the invention isto provide.A a process for themanufacture of varnishes from glyceride oils, or mixtures thereof, inwhich an.,

appreciable proportion of the unsaturation is. of'. the, conjugatedtype, which process maybe carried. out at approximately roomtemperature, can be controlled byan unskilled' operator to produceuniform products,v does not cause discoloration of thevarnish'byoxidation, gives higher yields than (Amberoi1F21)` 100iLinseed oil 15.6 Mineral spirits '22'31v (Solv'esso No. 100)Aromatichydrocarbon 9.0"

ducesa product of superior. color and drying and' lmfforming.characteristics. advantages. of .the invention will become. apparent:,fromzthe following description of my presently. pre-` ferred`processes andlproducts.` Y

In` accordance-with the .inventions a. drying oil, or drying oilmixture, having, on the averagenot less than vabout.` 5.5.carbonto-carbon. doubleY @bondsper molecule and-.having .not less thanabout 15% of the unsaturation in conjugated' form, `polymerizecl .at a..temperature in the range SGU-100` F. together withY an .oil-soluble.varnish-makers resin. in the` presence. .ofi a. volatile solvent andacatalyst comprising anl organic boron triluoride-complexin anY amountbetween 0.25% andz4'.0% expressed.r as percent equivalentboron-triuoride-based orrthe totalv nonsvolatile content of the batch..Ther reaction proceeds vrapidly anduniformly, at -rates satisfactoryfor commercial use; attemperatures far below the conventionalvarnish-making.` temperatures, and; with many varnish compositions,.even at room temperature. The rate and degree ofv polymerization may?conveniently bef determined by viscosity measurements. .For example',such. measurements can very easily be madezatsuitable: intervals by theGardner-Holdt tube method. When the reaction has proceeded to thedesired extent, as indicated bythevis'cosity reading, the

polymerization isfstoppedby the addition .of fa basic substance or bywashingrwith; water.

.This stage will be reached in from 4 minutes or less. to....3 or .4..hours. 'lfhereafter,l thesbatchuzis completed-:by clarifying it thefconventional'.

procedure. .inthecase where a, .basic .substanceriisl used', 011,. .the.reaction is .checked with water, byl separating the. yaqueousphasecontaining water-soluble hydrates ofthe boron trii'luoride, and `then`drying" by distillation or desi'ccation n The invention will be'urther'illustrated'by the following examples, in which `typical' oleoresinousvarnish compositions areconvertedj-by myprocess into varnishes of-enhanceddrying and nlm-formingcharacteristics.

.Example I An 18 gallon c` i1^length'varnish was'mad'e on theffollowin'gformula:

, Parts China-wood oil? 125 l Rosin-modied phenol-formaldehyde resinOther objects and.

tion was added, with stirring, 7.5 parts of borontriluoride-diethylether complex dissolved in 9 parts of Solvesso No. 100. The amount ofcatalyst was equivalent to 1.49% of boron triuoride,

based on the non-volatile constituents (oils plusk resin). The mixedlinseed and China-wood oils were then added and the batch stirred at 75F. continuously until the reaction had reached the desired stage asindicated by a viscosity of G-H on the Gardner-Holdt scale. Thisviscosity was reached in about 16 minutes. 7.5 parts of calcium oxidewere then stirred into the batch to check the reaction by inactivationof the catalyst. The batch was then completed by removing the excess oflime and the catalyst-lime complex from it by ltration in theconventional way.

Another batch of the same formulal was processed into a varnish in theconventional manner, involving heating the resin and China-wood oil inavarnish kettle to 565 F. in 40 minutes, addition of the linseed oil tolower the temperature, addition of the thinners atv 450 F., filteringand addition of solvent to obtain the same desired non-volatile content.Driers were added to each batch equivalent to 0.05% cobalt metal and0.4% lead metal, based on varnish non-volatile, and lms 0.003 inchthick'were formed on glass plates from each batch.

-'Comparative data on the batches are as follows:

Phenol-formaldehyde resin, (Bakelite-4036) 100 Linseed oil 39 Mineralspirits 270. Aromatic hydrocarbon (Solvesso #100) 36 The mixture of oilsof thisformula has about the same amount of unsaturation and conjugationas the oils of Example I. The resin was placed in a varnish kettle anddissolved inthe mineral spirits` in the cold. To the resulting solutionwas addedv 4 parts boron triuoride-diethyl ether complex, dissolved in36 parts aromatic hydrocarbon (Solvesso No. 100) (equivalent to 0.46%boron trifluoride by weight of the non-volatiles). The mixed linseed oiland China-wood oil were then added to the kettle with stirring, andstirring was continued at 79 F. Samples were taken at two minuteintervals for -viscosity determinations. The

4 the batch was then completed by clarifying it by filtration.

A second batch of the same formula was made into a varnish byconventional procedure involving heating the China-wood oil and resin ina varnish kettle to 540 F. in about 40 minutes, addition of the linseedoil, cooling to 450 F., addition of the thinners, ltration andincorporation of additional solvent to make up losses and restore thedesired non-volatile content, cobalt drier was incorporated in bothbatches, in the amount of 0.08% cobalt metal on non-volatiles, and lmsof `0.003 inch wet film thickness were drawn down on glass plates fromeach batch.

The two batches showed the following properties:

viscosityV reached D in about 6 minutes. About 4 parts. of calciumhydroxide, slurrie'd in a small amount of ethyl alcohol, were added tothe batch with continued stirring to stop the reaction and lThe mixtureof oils of this formula has, on

Example II Conventional Per cent non-volatile Viscosity Gardner- HoldtColor (Gardner 1933) 9 Total batch losses Dry, tack free Dry, throughand hat Hardness Toughness Water resistance 24 hour No whitening- NoWhitening.

immersion (at E).

Recovery after 24 hour Complete, hour. Complete, hour.

immersion (at 75 F.).

Ercample III A 40 gallon varnish was prepared with the followingformulation:

the average, about 7.3 carbon-to-carbon double bonds per molecule, ofwhich about 77% are in conjugated positions.

The resins were dissolved and the catalyst and oils added in the samemanner asin Examples I and II. The reaction was allowed to proceed forabout 4 minutes at 81 F., at which time a viscosity of E had beenattained. The reaction was then stopped and the varnish clariiied, as inEx- 5ample II.

Results were as follows:

Percent non-volatile 57 Viscosity (Gardner-Boldt) G-H Color (Gardner1933) 9-10 E-Total batch losses percent 0.3

Driers were incorporated in the amounts of 0.035% cobalt metal vand 0.3%lead metal, based on varnish non-volatile, and the varnish was drawndown on glass at 0.003. wet lm thickness. Drying and lm properties wereas follows:

Dry, tack free hours-- 7 Dry, through and hard do 18 HardnessGood-Excellent Toughness Excellent Water' resistance 24 hour immersion(at 75 F.) No whitening Recovery after 24 hours im- `mersion (at 75F.)Complete, hour rThe resin was dissolved and thel catalyst and oils addedto the resin solution in the manner described in preceding examples. Theamount of catalyst used was equivalent to about 1.2% boron centrationwithin the ranges stated above is the type or character of the dryingoil as respects its degree of unsaturation and average percentageconjugation.

trifluoride based on the varnish non-volatile con- The following tableillustrates some effects obtent. The reaction was allowed to proceed attained by varying the composition of the oil in 100 F. for about 80minutes, at which time a the formulas of Examples VI and VII. All theviscosity'of G-H had been attained. runs were made at 100 F.

Oil, Per Cent Polymerization Cliina-y Dehy- Double Per Cent Run ExampleWid Lllsied gstg PEF/. Coililgagrsl gl-gs Viscosity 2o so 6.5 2o 1.2 2sG 10 90 6.5 10 2.5 150 No Change. 75 5.9 45 1.2 10o G-H io so 5.7 34 2.530o o Results were as follows: Comparison of Run '2 with Run 1 shows thede- 20 crease in polymerization rate accompanying a de- Prceri n-vlame"G Eg crease in percent conjugation of the unsaturagsgrardr Igrs) o "l 89 tion, despite the fact that the total unsaturation Total batch loss"gege-egg o 3 expressed as the average number of double bonds permolecule is approximately equal in the two Driers were added in amountsequivalent t0 25 cases and the concentration of cataiyst is higher 0.07%ebalt metal and 05% leed metal based in Run 2. Runs 3 and 4 shows asimilar result 0n Varnish HOD-VOietile Content, and the Valllish with adiierent combination of oils. Comparison was drawn down on glass at0.003 inch wet film of Run 4 with Run 1 shows the decrease in poly-Jlfliekless. Drying and lm properties Were as merization rate resultingfrom a decrease in total UOWSI unsaturation, despite the largerpercentage of conjugation and the higher catalyst concentra- Bt:uaataajj::jif: i3 son in Run 4- From this ,das it is apparent thatHardness G00d EXeeuem both the. total unsaturation and .the degree. of'roughness Geod EXee11ent conJugation are important factors 1ndetermining Water resistance 24 heul. m 30 the suitability of an oil,or, mixture of oils, for mel-sion (at 75 F.) Slight Whitening use underthe conditions of my process. In gen Recovery after `24 hom. im eral, it-appears that as the total amount oi unmerson (at 75 E) Complete hoursaturation decreases the minimum percentage of conjugation necessary fora satisfactory poly- The process may be Varied considerably Wlth 40merization rate increases. The diiiculty of correspect to the type andComposition 0f the Val" relating these two factors and the influence ofnish Componente For instance' not only the Ta' other factors-as forinstance, the type and contiO 0f Oil t0 1esl but also the Composition 0fcentration of the resin to be used-makes it necthe O may be Vared- ThusI may use Chinaessary, at present, to determine the suitability wood oilor oiticica oil or other highly conjugated of a proposed Varnishcomposition by experioils, either alone or in a wide variety of mixturesmenta] trial, However, in generaly I prefer to other Oils, Such aslnseed Oil, dehyemploy an Oil, or mixture of oils having on the dratedCastor 011 fish 011s Seya bean Oil eteaverage not less than about 5.5carbon-to-carbon The composition of the fatty acids of most of doublebonds per molecule and having not less the Common drying Oils S known t0at least a 50 than about of the unsaturation in conju.. good degree ofapproximation. It is, therefore, gated fomL possible to estimate theaverage number of car- My process may -be Carried ou(-l Wii-,h anysuitbon-tO-Carbon double bonds per molecule 0f Oil able oil-solublevarnish makers resin. These in- Whch is a measure 0f totalunsaturatioii- Simclude the oil-soluble natural resins, such as theilarly, it is possible to estimate the average numoopeusy the dammen theEast Indias and resin,

ber of these double bonds which exist in conjugated positions. The ratioof this latter number to the'total number of double bonds is a measureof percentage conjugation. These estimates may be based on analyses ofthe fatty acid constituents of the oils as given in the literature. Thevalues I have estimated for some of the individual oils are:

Average Total Unset-mation Average Per Cent The most Vimportant factorgoverning the choice of. reaction temperature and catalyst conetc.; theoil soluble synthetic or semi-synthetic resins, such as the cumars,rosin esters of polyhydric alcohols, resin-modified phenolic resins, theso-called phenolic resins, rosin modified maleic resins, etc.; and alsosuch alkyd resins as possess satisfactory miscibility with oils, andgenerally any Varnish-makers resin which is oil-soluble under therequired processing conditions. Such resins I refer to herein asoilsoluble resins. The amount of resin may be such that the varnishcontains from 30% to '700% glyceride oil, or oils, by weight on theresin.

The varnish compositions employed in my process may contain any suitablesolvent, providing the solvent is a satisfactory medium for thedispersion or dissolution of the resin to be employed. Suitablesolvents, include the aromatic hydrocarbons, such as toluene and xylene,the higher solvency petroleum naphthas, mineral fac sogas;

.'satisfactoryf. dispersion ors-:solution `ofzthe resin,

abut-'I 'prefer '-.to` :include 130% ?to"2400% of:solvent by weighttoftheresin.

1 The catalystsI employ are substancesifrom `the group consisting of.lthes'coordinationr compounds :or complexes 1off=boronctrifluoride fandan Vorfganiczcomp'ound havingfone or rmorefpairs of "unshared electrons.@Typical substancesvvith which rboron .trifluoride ``forms' coordination:compounds fare diethylxether, ."dibutylether, uiphenyl methyl*."ether,` :methyl.alcohol,= ethyl; alcohol, phenol,face`to1'le,fme`thyl vethyl ketone-l-and acetic acid. The substancesfof`thisfclass are .referred to herein :as libcron V'1triiluoride-organiccompound coordina- "tion complexes. The coordination .complexes @areusually liquids or soluble isolids .-'and,in `many '-1'ca'ses, Varereadily :soluble :or jdispersiblef-tinYV the 1 'commonfvarnish'solventsand oils. 4=".Fhey::arefeasy to handle, and can bereadilyiandmniformly distributed throughout: the varnish batch Withoutproducing localized over-reaction. While different complexes I areVqualitatively equivalent, their individual:reactivitieszdepend on thebindingstrength of the coordinatingisubstanceandato adegree.at.least.upontheyolatility.of this substance. For'instance,"invarnishes Wehave found "fsorretimesmakeswit desirableto useclosedvessels which can be suitably protected againsten- 'tranceLof.iatmosphericfmoisture .'Stirring or mechanical agitation While notessential are generallyfdesirable'andathezpolymerization vessels are,therefore; preferably equipped for this purpose. `The vessels: may alsobe equipped `with j acketsV or coils1forheatingzorfcooling, although formany varnish compositions 'neither iis required. #Auxiliaryfzequipment,such as condensers 'or temperaf" turerecorders, Vmay be employedf-asdesired.

vlvlyprocess is -Well adapted to operation `ina continuous manner. Such`continuous operation `v may satisfactorily :be carried vout 4by makingthe :necessary -additions -of catalyst, oils, fand reac- -tionterminators, `to the `.resin ,(or varnish) fsolution atA- suitable:pcintsi or #stages While the` solution-.vis ilowing through ra systemof, pipes, tubes,

ol-..open orclosed chambers. f

the-'approximate order of 'reactivity of 14ftlfief'diethyl-ether,dibutyl ether-andfphenol complexes u Eto :be: vdie'thyl ethercozmpl'ex-dibutyl "ether comjplex` phenol complex. Wl'iile'ithe diethylj-ethercomplex is generally -useful,it1may be desirable in some circumstancesto use a less active catalyst, or to use a mixture of catalysts ofdiierent reactivities.

The amount of catalyst may be varied considerably depending upon thecharacter of theoil, the nature of the resin, the ratio of resin to oil,`the amount of solvent present, the temperature employed, the activityof the catalyst, and the polymerization rate desired.

Other conditions being the same the rate of polymerization increaseswith increase in the concentration of the catalyst. The magnitude of theeffect varies with the varnish composition, and the temperature but maybe illustrated by the following results obtained with the formula ofExample I. In Example I, with a catalyst concentration of 1.49% aviscosity of G-I-I was obtained at 75 F. in 16 minutes. When theoatalyst was reduced to 1.0% there was no appreciable increase in theoriginal viscosity (less than A) in 4 hours. On the other hand, when thecatalyst concentration was raised to 1.8%, rgelation occurred in 5minutes. In general, the preferred concentration of catalyst isequivalent to from 0.25% to 4.0% by Weight of boron trifluoride based onthe varnish non-volatile content (e. g. resin plus oil), when thenon-volatile content is in the normal range of about to 55%. For higheror lower non-volatile contents, the catalyst concentration may bedecreased or increased, respectively. Under these conditionspolymerization occurs readily, the time required ranging from 4-5minutes, or even less, to 3-4 hours, depending on the composition of thevarnish, the temperature and the concentration and activity of thecatalyst.

My process may be carried out in either open or closed vessels. Whilethe former have been used successfully, the detrimental eiect ofatmospheric moisture on the activity of the catalyst To arrest thereaction, I may employ. instead of thecalciumyoxide of the examples,yotheibasic substances, such as iotherv alkali metal or. `alkalinefearth `metal cxides,-alkali or alkaline earth metal carbonates or-hydroxides amines, or ammonia. Basic .substances form f` stable,relatively inert complexes-With .boron trifluoride.

Manycf these areA .solid fandainsoluble. .in the varnish and .can beremoved by ltration. LAA particularlysatis- .factory procedureistof-addfabout 1.5.to2.0 times y the -weight of catalyst .of-analkalineearth-oxide or-hydroxide -slurried .-in a small amountofa slowerialcohol. `The slurry is :preferably thor- 4-oughlydispersed in rthevarnish vluy-.stirring .or mechanical-agitation. During .the :stirringythe varnisn-generallybecomes considerably :lighter-in color, therebyindicating deactivation of the catalyst. The varnish then may beclarified by I'lltration, the use of a lter aid generally beingdesirable.

The polymerization rate increases with increase in the temperature. InExample VI a viscosity of G was obtained in 28 minutes at F. With thesame formula at 77 F. there was no significant increase in the originalviscosity (less than A) in minutes.

Because of the low temperatures and short reaction times characteristicof my process the loss in thinners and other volatile constituents ofthe batch is reduced to approximately onetenth the loss experienced whenthe varnish is bodied by the traditional cooking at high temperatures.In the conventional process the losses resulting from thermaldecomposition of the resins and the oils may amount to as much as 1% to-3% of the Weight of the resin and oil present in the initial charge,depending somewhat upon the temperatures employed for the particularcomposition. The loss in volatile solvents, Which normally are added tothe kettle after the temperature has reached 400-480 F., to checkpolymerization, may be as great as 2%- 3% of the added solvent.

The products of my process are radically and fundamentally differentfrom and superior to the products of the ordinary processes employingheat bodying of the oils. I have found that my process causes nodiscoloration of the oils or resins, which result I attribute to thepresence of the thinner and to the low temperatures employed. Thecompleted varnish products are superior in color by several units on thestandard scale. Most surprising is the behaviour of the products of myprocess during drying. The varnishes dry much faster than varnishes ofidentical formulation which have been made by the standard meth- 1l odsinvolving heating to temperatures above 400 F. Having thus fullydisclosed my invention, I claim:

1. The process for the production of an oleoresinous varnish of improvedcolor and drying characteristics which comprises forming a solution ordispersion in a hydrocarbon solvent of an oil-soluble varnish resin andan unsaturated glyceride drying oil, the weight of the solvent beingfrom 30% to 2400% of the Weight of the resin,*and the oil presentcontaining on the average more than 5.5 double bonds per molecule ofoil, of which at least 15% are in conjugated position, and acoordination complex of boron trifluoride and an organic compoundselected from the class consisting of ethers, alcohols, acids, andketones equivalent to 0.25% to 4.0% by weight of boron triuoride basedon they Varnish nonvolatilev content, maintaining said mixture at atemperature in the range 60 F. to 100 F. for less than 4 hours and untilthe viscosity reaches a varnish consistency, adding a basic substance tothe resulting varnish in an amount sufficient rof the resin, and theoil'having 'on the average more than 5.5 double bonds per molecule ofoil of which more than 15% are in conjugated position, and acoordination complex of boron triuoride and an organic compound selectedfrom the class consisting of ethers, alcohols, acids, and ketonesequivalent to 0.25% to 4.0% by weight of boron triuoride based on thevarnish non-volatile content, maintaining said mixture at a temperaturein the range of F. to 100 F. for less than 4 hours until the viscosityreaches a varnish consistency, adding Water to the resulting varnish inan amount at least suflicient to form watersoluble hydrates withsubstantially al1 of the boron trii'luoride-organic compoundcoordination complex present in the mixture, and then separating andremoving the aqueous phase.

3. An oleoresinous varnish of improved drying characteristics and colorcomprising the product of the process of claim 1.

4. An oleoresinous varnish of improved drying characteristics and colorcomprising the product of the process of claim 2.

JOI-IN J. BRADLEY, JR.

REFERENCES CITED The following references areof record in the le of thispatent:

UNITED STATES PATENTS Number Name Date 2,229,305 Pratt Jan. 21, 19412,380,394 Berger et ai. July 31, 1945 2,440,000 Berger et al Apr. 20,1948 2,441,105 Socolofsky May 4, 1948

1. THE PROCESS FOR THE PRODUCTION OF AN OLEORESINOUS VARNISH OF IMPROVEDCOLOR AND DRYING CHARACTERISTICS WHICH COMPRISES FORMING A SOLUTION OFDISPERSION IN A HYDROCARBON SOLVENT OF AN OIL-SOLUBLE VARNISH RESIN ANDAN UNSATURATED GLYCERIDE DRYING OIL, THE WEIGHT OF THE SOLVENT BEINGFROM 30% TO 2400% OF THE WEIGHT OF THE RESIN, AND THE OIL PRESENTCONTAINING ON THE AVERAGE MORE THAN 5.5 DOUBLE BONDS PER MOLECULE OFOIL, OF WHICH AT LEAST 15% ARE IN CONJUGATED POSITION, AND ACOORDINATION COMPLEX OF BORON TRIFLUORIDE AND AN ORGANIC COMPOUNDSELECTED FROM THE CLASS CONSISTING OF ETHERS, ALCOHOLS, ACIDS, ANDKETONES EQUIVALENT TO 0.25% TO 4.0% BY WEIGHT OF BORON TRIFLUORIDE BASEDON THE VARNIS NONVOLATILE CONTENT, MAINTAINING SAID MIXTURE AT ATEMPERATURE IN THE RANGE 60* F. TO 100* F. FOR LESS THAN 4 HOURS ANDUNTIL THE VISCOSITY REACHES A VARNIS CONSISTENCY, ADDING A BASICSUBSTANCE TO THE RESULTING VARNISH IN AN AMOUNT SUFFICIENT TO REACT WITHSUBSTANTIALLY ALL OF THE BORON TRIFLUORIDE-ORGANIC COMPOUND COORDINATIONCOMPLEX PRESENT IN THE MIXTURE, AND REMOVING THE REACTION PRODUCT FROMTHE VARNISH.